In recent years, evidence for new physics
has started emerging from measurements of several observables in flavor physics. Many of these observables are related to decays induced by the quark level transition \(b \rightarrow s \ell \ell \)  (\(\ell =e,\mu \) ). The most enticing discrepancies are in the measurements of lepton flavour universality (LFU) testing ratios \(R_K \equiv \Gamma (B^+ \rightarrow K^+ \mu ^+ \mu ^-)/\Gamma (B^+ \rightarrow K^+ e^+ e^-)\)  [1]} and \(R_{K^*} \equiv \Gamma (B^0 \rightarrow K^{*0} \mu ^+ \mu ^-)/\Gamma (B^0 \rightarrow K^{*0} e^+ e^-)\)  [2]} which disagree with the SM prediction of \(\approx 1\)  [3]}, [4]}, [5]}, [6]} at the level of 3.1 and 2.5\(\sigma \) , respectively.
